diff options
| author | Dave Chinner <david@fromorbit.com> | 2013-06-27 16:04:52 +1000 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2013-06-27 13:33:11 -0500 |
| commit | 5f6bed76c0c85cb4d04885a5de00b629deee550b (patch) | |
| tree | d2a39b931b367da3a797472c95d886d9e3b6c989 /fs/xfs/xfs_buf_item.h | |
| parent | fd63875cc4cd60b9e5c609c24d75eaaad3e6d1c4 (diff) | |
xfs: Introduce an ordered buffer item
If we have a buffer that we have modified but we do not wish to
physically log in a transaction (e.g. we've logged a logical
change), we still need to ensure that transactional integrity is
maintained. Hence we must not move the tail of the log past the
transaction that the buffer is associated with before the buffer is
written to disk.
This means these special buffers still need to be included in the
transaction and added to the AIL just like a normal buffer, but we
do not want the modifications to the buffer written into the
transaction. IOWs, what we want is an "ordered buffer" that
maintains the same transactional life cycle as a physically logged
buffer, just without the transcribing of the modifications to the
log.
Hence we need to flag the buffer as an "ordered buffer" to avoid
including it in vector size calculations or formatting during the
transaction. Once the transaction is committed, the buffer appears
for all intents to be the same as a physically logged buffer as it
transitions through the log and AIL.
Relogging will also work just fine for such an ordered buffer - the
logical transaction will be replayed before the subsequent
modifications that relog the buffer, so everything will be
reconstructed correctly by recovery.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_buf_item.h')
| -rw-r--r-- | fs/xfs/xfs_buf_item.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h index 2573d2a75fc8..0f1c247dc680 100644 --- a/fs/xfs/xfs_buf_item.h +++ b/fs/xfs/xfs_buf_item.h @@ -120,6 +120,7 @@ xfs_blft_from_flags(struct xfs_buf_log_format *blf) #define XFS_BLI_INODE_ALLOC_BUF 0x10 #define XFS_BLI_STALE_INODE 0x20 #define XFS_BLI_INODE_BUF 0x40 +#define XFS_BLI_ORDERED 0x80 #define XFS_BLI_FLAGS \ { XFS_BLI_HOLD, "HOLD" }, \ @@ -128,7 +129,8 @@ xfs_blft_from_flags(struct xfs_buf_log_format *blf) { XFS_BLI_LOGGED, "LOGGED" }, \ { XFS_BLI_INODE_ALLOC_BUF, "INODE_ALLOC" }, \ { XFS_BLI_STALE_INODE, "STALE_INODE" }, \ - { XFS_BLI_INODE_BUF, "INODE_BUF" } + { XFS_BLI_INODE_BUF, "INODE_BUF" }, \ + { XFS_BLI_ORDERED, "ORDERED" } #ifdef __KERNEL__ |